Elevator doorlatch



Feb. 21, 1933. w. A. HUTTON ELEVATOR DOORLATCH Filed Oct. 3, 1929 2 Sheets-Sheet l 0 Y m Wm m cm W A Feb. 21, 1933. w. A. HUTTON 1,898,450

ELEVATOR DOORLATCH 2 Sheets-Sheet 2 Filed Oct. 5, 1929 INVENTOR Way/4am {fix alien r; y i z E a l h lfiNEY Patented Feb. 21, 1933 UNITED STATES WILLIAM A. HUT'ION, 0F SEATTLE, WASHINGTON ELEVATOR DOORLATCH Application filed October 3, 1929. Serial No. 397,043.

My invention relates to improvements in elevator door locks or latches of the combined electrical and mechanical interlock type and the general object of my invention is to improve and simplify the construction of latches of this type and to render said latches more eflicient and reliable in operation.

Other objects are to provide an elevator door latch of rugged and efficient construction which is connected with an electric switch in such a manner as to close said switch when the latch is latched and to open said switch when the latch is in the unlatched position, said latch being free from springs and being operated by weights as respects all parts where automatic operation is required, all of the mechanism of the latch and switch being enclosed within a strong metal box by which it is fully protected, theswitch being located at the extreme top of the box where it can not possibly be reached from the outside, and in such a position as to prevent it from becoming short circuited by broken parts in case anything in the latch or switch should break.

Another object is to provide a latch of,

making it possible for a person, (as the elevator operator or janitor), to get out of the elevator car and close the door from the outside leaving said door unlatched so that he may quickly and easily re-enter the car, it being impossible to move the elevator car when the door is thus left unlatched without first latching said door, thus making it impossible to leave a door on an elevator shaft unlatched and open to access from the outside after the elevator car has been taken away from the inside.

In connection with passenger elevators, it is desirable as a matter of public safety, and is frequently required by law and ordinance, that the elevators shall be equipped with electrical control means which makes it impossible to start or operate the elevator car except when the door is properly closed and when the door is closed and open when the door is open. This makesit impossible to move the elevator car at all except when all of the doors of the shaft are closed and these switches are usually connected with the door latches so that the car can not be moved until the doors" are properly latched or fastened.

My invention complies fully with the requirements above set forth without seriously slowing up the operation of the elevator or requiring excessive labor; and attention on the part of the operator.

In the use of elevators, especially by janitors and watchmen in buildings, it frequently happens that the person using the elevator will want to get outof the car and leave the door in such a condition that he can reenter quickly and easily. The usual type of elevator door can not be completely closed without latching and is not easy to open from the outside when it is latched and it is common practice for the person leaving the elevator, to leave the door ajar so that he can re-enter easily. When an elevator door is left ajar it attracts public attention and someone is liable to close and latch the door or to tamper with the car or take the car away. If the door is closed in this manner it will latch and make it diflicult for the proper person to re-enter the car. If the car is taken away by an unauthorized person leaving the door either open or closed it opens up the possibility of a serious accident in case the person who left I the car fails to notice that the car is gone,

when he returns, and opens the door and falls into the elevator shaft. Numerous accidents have happened in this way. My elevator door latch overcomes these difficulties by making it possible to completely making it possible to use a latch on the door, which positively can not be released from the outside of the shaft and which no person will attempt to release from the outside of the shaft.

Other and more specific objects of the in vention will be apparent from the follow ing description taken in connection with the accompanying drawings.

In the drawings Fig. 1, is an elevation with the cover removed of my elevator door latch as it may appear from the inside of the shaft when in a latched position with the switch closed, only a fragment of the elevator shaft and door being shown.

Fig. 2 is a similar view showing the latch unlatched and the switch open and the door slightly withdrawn.

Fig. 3 is a similar view showing the parts of the latch in an unlatched position into which they may be moved just before opening the door.

Fig. 1 is a cross section on broken line 1-4 of Fig. 1, showing the cover for the bolt members.

Fig. 5 is a sectional view through the latch housing substantially on broken line 55 of Fig. 1.

Fig. 6 is a detached perspective view of the main latch and switch operating member.

Figs. 7 and 8 are detached perspective views of other parts of the latch.

Like reference numerals designate like parts throughout the several views.

Referring to the drawings I show a typical installation of my invention in which 10 is a door mounted for sliding movement in the usual manner and 11 is a fixed portion of an elevator shaft or car on which the switch and catch portions of the latch are mounted. The latch will ordinarily be installed on the doors of the elevator shaft and for the purpose of this description the door 10 is regarded as an elevator shaft door and the fixed portion 11 as a part of the elevator shaft. It will be understood however, that the latch is equally well adapted for use on an elevator car and the sliding door connected therewith.

The portions which are mounted on the door 10 embody a horizontal sliding latch bolt 12 and a horizontal sliding trip bolt 13, both supported for longitudinal movement within guides 1 which are secured to the frame bars of the door 10. Stops 15 are secured to the latch bolt 12 to limit the movement of the same in both directions. A notch 16 is provided in the upper edge of the latch bolt 12 near the outer end to leave an inclined shoulder 17 with which a catch member 28 may engage as hereinafter set forth. The latch bolt 12 rests upon the edge of the trip bolt 13 and is slidable lengthwise thereon and roller or ball bearings 18 may be provided between the edges of said two bolts to reduce friction, as shown by dotted lines in Fig. 1. The two bolt members are moved longitudinally relative to each other and within the guides 14: by a hand lever 19 which is fulcrumed on a pivot 20 in the rear end of the latch bolt 12 and has a forked bottom end. 21 which fits over a roller 22 which is mounted on the rear end of the trip bolt 13 through the intermediacy of a mounting plate 23. When the bolts 12 and 13 are in latched position shown in Fig. 1, the hand lever 19 is tilted to the left. f a pull is exerted on said lever 19 when it is in this latched position the first movement of said lever will move the trip bol forward, to the left, and release the latch bolt and further movement will withdraw both bolts 12 and 13 into the position shown in Fig. 2, after which a further pull on the hand lever 19 will pull the door 10 open. When the hand lever 19 is in the released position shown in Fig. 2 a push to the left will first retract the trip bolt 13 relative to the latch bolt 12 and will then close the door and cause the latch bolt to be engaged by a catch member 26 as hereinafter set forth. The hand lever 19 has stops 24 provided thereon to engage with the top edge of the latch bolt 12 and limit the tilting movement of said hand lever in both directions.

The catch mechanism and switch are completely enclosed within a housing 25 that is mounted on the fixed frame portion 11.

The mechanism for effecting a locking en agement with the bolt, comprises a catch member 26 fulcrumed on a rigid stud pin 27 in the housing 25 and provided with a hook like portion or pawl 28 adapted to drop into the notch 16 and lock into engagement with the shoulder 17 of the latch bolt 12. A relatively long notch 29 is provided in the catch member 26 to afford clearance for the end of the latch bolt 12 and an integral weight 30 is formed on said latch member above the notch 29 and pawl 28 for urging said latch member into a locked position.

The rear end of the catch member 26 has a switch plate 31, of insulating material, secured thereto by bolts 82. The switch plate 31 carries a roller 33 of conductive material which is arranged to fit between the curved lower ends of two spring pressed contact members 341 on a switch 35 and close the switch when the latch member 26 is in the engaged position shown in Fig. 1. When said latch member 26 is in the released position shown in Fig. 2 the roller 33 will be withdrawn from the contact members 3-1 and the switch will be open. Circuit Wires 36, forming a part of the control circuit for the elevator car are connected with the switch 35. The switch 35 is of standard construction and the control circuit connected with said switch is of well known form. For this reason these parts'will not be herein described in detail.

The latch member 26 is moved into released position relative to the latch bolt 12 by a trip member 37 which is fulcrumed on a pivot 38 rigidly secured to the housing 25. The top end 35) ofthe trip member 37 is inclined, as shown, and is arranged to engage with a shoulder 40 formed on the latch member 26 at the bottom of the weight portion 30 so as to lift the weighted end of said latch member into the position shown in Fig. 2. The lower end of the trip member 37 is provided with an out-- wardly projecting pin 41 disposed in alignment with the end of the trip bolt 13 and arranged to be engaged by said trip bolt to tilt the trip member'37 and raise the latch member 26 into released position as shown in Fig. 3 when a pull to the right is exerted on the hand lever 19. As soon as the pawl 28 is released the end of the. trip bolt 13 moves away from the pin 41 and the trip member 37 drops back into the position shown in Fig. 1, with the flat front edge 42 of said trip member restin against the housing '25, leaving the latch member 26 held in released position by weight means described in the following paragraph.

The weight means for holding the latch member 26 released and the switch 35 open comprises a weight portion 43 suspended by an upwardly extending bell crank arm 44 from the pivot stud 27 and having a forwardly extending arm 45 upon which is mounted a roller 46 which is arranged to be engaged by the end of the latch bolt 12 when said latch bolt is in the engaged position. The end of the weight furthest removed from the arms 44 and 45 is connected by a link 47 with the rear end of the latch member 26, a slot 48 in the link 47 for receiving the bolt 49 by which it is connected with the latch member 26 serving to permit a desirable amount of relative movement between the latch member 26 and weight 43. A stop 50 is provided for the weight to rest on in its lowermost position.

hen the latch mechanism is in engaged position the end of the latch bolt 12 will engage the roller 46 and hold the weight 43 in the raised position shown in Fig. 1. V'Vhen the latch member 26 is moved into released position by inward movement of the trip bar 13 the weight 43 will remain in the raised position and the bolt 49 will move downwardly in the slot 48 until the pawl 23 releases the latch bolt 12 whereupon the latch bolt 12 and trip bolt 13 will both begin to move to the right, releasing the roller 46 and permitting the weight 43 to drop down and hold the latch member 26 released and the switch 35 openuntil the door is again closed, the weight 43 being heavy enough to overbalance the weight 30.

In the operation of closing the door the slot 48 allows the weight 43 to be lifted up without moving the latch member 26 when shown in Fig. 4. This housing is omitted from the other figures so as to show the mechanism more clearly.

In the operation of the elevator door latch, when the latch is in the engaged position shown'in Fig. 1 a pull to the right on hand lever 19 will first move the trip bolt 13 to the left engaging the stud pin 41 on the trip member 37 and causing said trip member to simultaneously lift the latch member 26 into released position and open the switch. vAs soon as the latch bolt 12 is released the door 10 will be free to open and the ends of trip bolt 13 and latch bolt 12 will move awayfrom the stud pin 41 and roller 46 respectively. This permits the trip member 37 to drop back into released position and permits the weight 43 to drop down and hold the latch member 26 released and the switch open. It will thus be seen that the latch can not be disengaged without opening the switch and that the switch can not be closed without closing the door and engaging the latch. This makes it impossible to start the elevator car when the door 10 is open or the latch unlatched and also makes it impossible to open the door 10 or release the latch without stopping the car. The provision of the sliding bolts 12 and 13 make it possible to close the door 10 from the outside without latching the same or closing the switch thus allowing an authorized person to leave the elevator car with the door 10 closed and re-enter quickly and easilywithout leaving the door 10 and the elevator car in a dangerous position. If any other person enters the elevator car and takes it away when the door is thus left closed and unlatchedhe must first close and latch the door thus making it impossible for the person that left the elevator car to return and fall down the elevator shaft before he is aware that the car is gone. To close and latch the door 10 a push is exerted on the hand lever 19. This moves both bolts 12 and 13 to the left. As the door closes the latch bolt enters the housing 25 through a notch 51 and strikes against the roller 46. This lifts the weight 43, and, when the notch 16 comes under the pawl 26, the weight 30 snaps the pawl 28 down into said notch 16 and closes the switch 35. The bolts 12 and 13 are relatively thin and do not take up a great deal of space and-the other parts are compact and occupy little room thus making it possible to install this look on its 'iis

doors where only a small clearance is allowed between the doors of the shaft and the elevator cars.

It will be noted that the notch 16 is con siderably longer than the pawl 28 and that the pin l1 is at a substantial distance from the end of the trip bar 13 when the door is closed and latched as in Fig. 1. This makes it impossible to damage the several elements of the latch by jamming the door in case the bumpers 52 which are provided between the door 10 and frame 11 should become worn or entirely removed. This reduces the necessity of frequent and careful inspection of the bumpers 52 as is required in constructions where these safety features are not provided.

The guide plate 14: serves as a guard and covers both sides of the bolts 12 and 13 and prevents access to said bolts from the ou side through the crack between the door and the shaft when the door is closed, making it impossible to tamper with the bolts from the outside. Said plate ll is further long enough to overhang the ends of the bolts 12 and 13 when said bolts are retracted thus obviating the danger of catching the clothes on the ends of such bolts.

The foregoing description and accompanying drawings clearly disclose a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims.

I claim:

1. The combination with a sliding door movable horizontally to close against a relatively fixed frame, of a latch bolt slidably supported on said door for horizontal retractile movement within the limits of said door and inaccessable from the exterior of the door when fully retracted whereby the door may be closed leaving the latch bolt in retracted position, means connected with the latch bolt for normally moving said latch bolt into outwardly projected position beyond the edge of said door when force is exerted thereon tending to close said door said means being incapable of moving said latch bolt away from the retracted position in the absence of such closing force and latch means on the frame for engaging the latch bolt to hold the door in closed position, said latch means being clear of said latch bolt when the latch bolt is retracted and the door closed.

2. In an elevator door latch, the combination with a sliding door and relatively fixed frame means at the side of said door, of a latch bolt and a trip bolt both supported for sliding movement on the door and slidable relative to each other, latch means on the frame for engaging and holding said latch bolt and devices operated by the trip bolt for releasing said latch means.

3. The apparatus as claimed in claim 2 in which the latch bolt and the trip bolt are clear of the latch means when retracted into the door allowing said door to be entirely closed without latching.

4. In an elevator door latch, the combination with a sliding door and relatively fixed frame means at the side of said door, of a latch bolt and a trip bolt both supported for sliding movement on the door and. slidable relative to each other, a hand lever pivoted on the latch bolt and having a slot and pin connection with the trip bolt for slidably moving said bolts relative to each other and to the door, latch means on the frame, for interlocking with the latch bolt and a releasing member on the frame operated by the trip bolt for releasing said latch means.

5. In an elevator door latch, the combination with a sliding door and relatively fixed frame means at the side of said door, of a latch bolt and a trip bolt supported for sliding movement on the door and slidable rela tive to eaca other, latch means on the frame for locking into the end of tne latch bolt, means operated by said trip bolt for releasing said latch means and a counterweight for holding said latch means in released position.

6. In an elevator door latch, the combination with a sliding door and relatively fixed frame means at the side of said door, of a latch bolt and a trip bolt supported for sliding movement on the door and slidable relative to each other, latch means on the frame for locking into the end of the latch bolt, means operated by said trip bolt for releasing said latch means, a counterweight for holding said latch means in released position and means arranged to be engaged by the end of said latch bolt for lifting said counterweight to permit engagement of said latch bolt by said latch means.

7. In an elevator door latch, the combina tion with a sliding door and relatively fixed frame means at the side of said door, of a latch bolt and a trip bolt supported for sliding movement on the door and slidable relative to each other, latch means on the frame for locking into the end of the latch bolt, means operated by said trip bolt for releas ing said latch means, an electric s vitch onerated by said latch means for closing an elevator control circuit when said latch means is latched and opening said circuit when said latch means is released. a counterweight for holding said latch means released and means operating by the latch bolt for lifting the counterweight when the latch bolt is in the engaged position.

8. The apparatus as claimed in claim 7 in which a weight is provided on the latch means for closing the switch and moving the latch means into locked engagement with the latch bolt when the counterweight is lifted.

9. The apparatus as claimed in claim 7 l in which the latch bolt and the trip bolt are clear of the latch means when retracted into the door thereby allowing said door to be fully closed without closing the switch or engaging the latch mechanism.

10. In an elevator door latch the combination with a sliding door and a relatively fixed frame at the side of said door, of a latch bolt supported for sliding movement on the inside of the door, a trip bolt also supported for sliding movement on the inside of the door, a lever arm for moving both said bolts slidably in said door and slidably relative to each other and for further moving said sliding door, a latch receptacle on the frame, a latch member in the receptacle for looking into engagement with the end of said latch bolt, a releasing member arranged to be moved by engagement with the end of said trip bolt for releasing said latch member, a counterweight for holding said latch member in released means arranged to be engaged by the latch bolt for lifting the counterweight when the latch bolt is moved into position for engagement by said latch member and a weight on said latch member for engaging the latch member with the latch bolt when the counterwei 'ht is raised.

11. in an elevator door latch the combination with a sliding door and a relatively fixed frame at the side of said door, of a latch bolt supported for sliding movement on the inside of the door, a trip bolt also supported for sliding movement on the inside of the door, a lever arm for moving both said bolts slidably in said door and slidably relative to each other and for further moving said sliding door, a latch receptacle on the frame, a latch member in the receptacle for looking into engagement with the end of said latch bolt, a releasing member arranged to be moved by engagement with the end of said trip bolt for releasing said latch member, a switch connected with an elevator control circuit and arranged to be opened and closed by movement of said latch member and weight means 00- operating with said latch bolt and said latch member for moving said latch member into locked and unlocked position and opening and closing said switch.

12. In an elevator door latch, the combination with a sliding door arranged to close against a relatively fixed frame, of a latch housing secured to the frame, a latch member fulcrumed within the latch housing and having a pawl on one end, a weight on said latch member for urging the same into a latched position, an electric switch, means connected with the outer end of the latch member for opening the-switch when the position,

latch member is retracted and for closing the switch when the latch member is en gaged, a counterweight suspended from the fulcrum of said latch member, a link connecting the latch member with the counterweight by means including a slot and pin connection, said counterwei ht being ar ranged to hold the latch memloer in released position, a releasing member pivotally mounted under the weighted portion of said latch member, a latch bolt and a trip bolt slidably mounted 011 said door, said latch bolt having a notch near its outer end arranged to be engaged by the pawl on said latch member, means for moving said latch bolt and said trip bolt slidably relative to each other and to the door, means on the releasing member arranged to be engaged by the end of the trip bolt to release the latch member and means on said counterweight arranged to be engaged by the end of said latch bolt to lift the counterweight when the latch bolt is moved to the latched position.

The foregoing specification signed at Seattle, Wash, this 25th day of Sept, 1929.

WILLIAM A. HUTTON. 

